"We are temporarily not permitting computers with the Vista operating system to be connected to our networks," Michael Baum, a NIST spokesman, said Tuesday. The organization's technology staff is testing NIST applications and evaluating the security in Windows Vista. The same holds true for Internet Explorer 7 and Office 2007, he said.

It is not unusual that agencies aren't rushing to install major software updates. Large organizations in particular tend to do a lot of testing before upgrading. The same happened when Microsoft released Service Pack 2 for Windows XP. The actions by DOT, which employs about 54,000 people, and NIST, with 2,900 employees, were first reported by Information Week.

The DOT also bans Vista, Office 2007 and IE 7. In addition to compatibility concerns, the department lists cost, available funding and a pending headquarters move as reasons not to upgrade, according to a DOT memo dated January 19 (click for PDF of the memo). The memo is still current, a DOT representative said Tuesday.

"There appears to be no compelling technical or business case for upgrading to these new Microsoft software products," according to the memo. The department plans to issue an update next month to clarify its strategy for 2008 and beyond, the representative said.

In a statement, Microsoft said it is working with many government agencies to help them adopt its latest products. "We respect the customer's decision," the company said.

The Federal Aviation Administration (FAA), the largest organization under the DOT, is taking the opportunity to consider alternatives to Microsoft's operating system and productivity software, said Tammy Jones, an FAA spokeswoman. This includes including running Linux on desktops and using Google's online applications, she said.

"We're trying to see what the cost impact would be to the FAA to convert to the new Microsoft products," Jones said. "We want to explore what some of the alternatives are. Google is one that we're looking at, so is Linux." The FAA has about 45,000 employees.

"Business customers should take a cautious approach to adopting new Windows technologies and need to go through a normal evaluation cycle," IDC analyst Al Gillen wrote in a recent report. "Most organizations should incorporate a move to Windows Vista in their longer-term road map--unless they are planning to move toward competitive solutions."

Many organizations will need up to 18 months after the Vista ship date to verify their applications, get other software makers to support the operating system and run tests, analyst firm Gartner said in a December report. "Sooner or later, most organizations will deploy Windows Vista," Gartner's analysts said.